ATMEGA649A-AU Atmel, ATMEGA649A-AU Datasheet - Page 195

• Manufacturer Part Number: ATMEGA649A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA649A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.10 Examples of Baud Rate Setting
Table 19-4.
1.
8284A–AVR–10/10
Baud
Rate
(bps)
Max.
115.2k
230.4k
14.4k
19.2k
28.8k
38.4k
57.6k
76.8k
2400
4800
9600
250k
(1)
UBRR = 0, Error = 0.0%
UBRRn
25
12
6
3
2
1
1
0
–
–
–
–
62.5 kbps
Examples of UBRRn Settings for Commonly Used Oscillator Frequencies
U2Xn = 0
f
Error
-18.6%
osc
-7.0%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
–
–
= 1.0000 MHz
For standard crystal and resonator frequencies, the most commonly used baud rates for asyn-
chronous operation can be generated by using the UBRRn settings in
UBRRn values which yield an actual baud rate differing less than 0.5% from the target baud
rate, are bold in the table. Higher error ratings are acceptable, but the Receiver will have less
noise resistance when the error ratings are high, especially for large serial frames (see
chronous Operational Range” on page
equation:
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
UBRRn
51
25
12
8
6
3
2
1
1
0
–
–
U2Xn = 1
125 kbps
Error
-18.6%
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
UBRRn
47
23
11
7
5
3
2
1
1
0
–
–
115.2 kbps
Error[%]
U2Xn = 0
f
osc
Error
-25.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
=
= 1.8432 MHz
–
–
⎛
⎝
BaudRate
------------------------------------------------------- - 1
192). The error values are calculated using the following
UBRRn
BaudRate
95
47
23
15
11
230.4 kbps
7
5
3
2
1
0
–
U2Xn = 1
Closest Match
Error
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
–
–
UBRRn
⎞
⎠
•
51
25
12
8
6
3
2
1
1
0
–
–
100%
U2Xn = 0
125 kbps
f
osc
Error
-18.6%
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
Table 19-3 on page
–
–
= 2.0000 MHz
UBRRn
103
51
25
16
12
8
6
3
2
1
–
0
U2Xn = 1
250 kbps
Error
-3.5%
-7.0%
”Asyn-
0.2%
0.2%
0.2%
2.1%
0.2%
8.5%
8.5%
8.5%
0.0%
–
193.
195